Phil Studds, White Young Green Environmental, and Stephan Ruzicka, Whitbybird Engineers. This note was first published in GE’s June 2005 issue.
Pragmatic and efficient management of risks arising from historically contaminated sites is a key prerequisite for successful redevelopment of brownfield land.
The risk management framework comprises identification and assessment of potential hazards, estimation of the risks posed by these hazards and evaluation of their importance (eg. source-pathway-receptor analysis and identification of significant pollutant linkages).
Where the identified risks are deemed unacceptable, suitable risk management solutions are developed for their mitigation. The general objective for these solutions, also known as remedial measures, is risk reduction through breaking the pollutant linkage. This can be achieved by source reduction, pathway management, control of the receptor exposure, or by a combination of these.
Careful selection of remediation methods is critical if resources are not to be wasted and environmental risks are to be minimised. However, despite the growing number of remed ial solutions available, many risk management decisions are still largely intuitive and impulsive, driven by the experience, or lack of it, of key stakeholders (land owner, consultant, regulator).
Although the range of processbased remediation technologies is steadily growing, only a limited number have been tested on a commercial scale, have a proven track record or the necessary licences to operate. Some of the remediation technologies available commercially in the UK are shown in Table 1.
This article summarises the procedures involved in the decision making process for contaminated land management and presents a tiered approach to selection of an appropriate risk management solution using an example case study.